Common faults and solutions of sanding machines

Sanding machines are used to sand (or grind) various boards and woodworking components with abrasive tools. Sanding machines are widely used in the woodworking and furniture industries, and are in high demand with many varieties. They have been developing at a fast pace in recent years.

The sanding machine is characterised by its adaptability. It can improve the dimensional accuracy of the work as well as the surface roughness of the plywood; it can process larger widths of plywood as well as narrow ones; it can process various flat surfaces as well as curved surfaces; it can be used for mass production as well as for small batch production.

When sanding machines are in operation, various faults can occur. You should learn to handle and troubleshoot them in a timely manner. Proper maintenance and care will make the life of the sander longer.

Failure analysis of sanding machines

During the operation of the machine, a number of faults will often occur. These faults should be eliminated in time. If they are not handled properly, they may affect production and increase costs. This requires the operator to be familiar with the operating regulations, to be skilled in operation and to remove them in a timely manner. Some faults are not serious when they are found, but if they are not handled appropriately, they can cause major faults and seriously affect production. The following is an analysis of common faults in sanding machines.

1.The sander limit switch is not working

There are limit switches on both sides of the belt, so that when the belt swings out of order and deviates to one side, the belt is released and the main motor stops automatically when the limit switch is touched. The belt is thus effectively protected. Once the limit switch is out of order, it can cause damage to the sanding belt and generate sparks in the abrasive frame, even causing a fire.

Solution: The limit switch should be checked frequently to see if the action is reliable.

2. The belt deviates from the normal track

This situation is generally caused by improper adjustment. Normal sanding belt swing amplitude for 15-20mm, swing frequency for 15-20 times / min, swing speed moderate and swing into the swing out speed consistent. If in a non-normal state for a long time, sthe belt may  deviates from the normal track. Especially the pendulum into the pendulum out of the speed is not consistent, more likely to trigger abnormal stop phenomenon; also can cause photoelectric switch damage, solenoid valve damage, swing cylinder cylinder damage.

Solution: poor dust absorption, high dust concentration will affect the normal work of the photoelectric tube, but also cause the sand belt run-off; damaged accessories should be replaced in time to damage and improve the dust removal effect.

3.Sanding belt wrinkles

Once the sanding belt is wrinkled, it cannot be used again. Generally, there are three possibilities to cause wrinkling of the sanding belt: the abrasion of the sanding roller and tensioning roller; the wrinkling of the sanding belt is caused by moisture and softness; the surface of the sanding roller is rusty and rough when the sanding machine is not used for a long time, and the sanding belt has difficulty in swinging.

Solution: The belt an be used to dry sun-drying methods of treatment; you can remove rust on the roller or sanding with finer sandpaper.

4.The sanding belt is broken

There are several reasons why sanding belts may break: firstly, the belt may run off. Secondly, the belt may not be replaced in time. Thirdly, the sanding load may be too high. Fourthly, the belt may encounter hard objects during the sanding process. And fifthly, the belt itself may be of poor quality.

Solution: Abrasive belt fracture should be avoided as far as possible, otherwise it may cause a fire. When the current occurs abnormally, the sanding belt should be observed to see if it has been worn blunt, if so it should be replaced in time.

5.Abnormal vibration of the main bearing housing

Under normal circumstances the main bearing seat vibration is very small. An experienced operator will be able to judge whether it is normal with a single touch. In the field generally do not have the conditions with the instrument measurement, but can be used and other bearing seat comparison to judge, but also from the sanding plate surface superiority to judge.

Solution: When the bearing seat vibration abnormalities occur, it can be considered that there are two causes. One is the bearing damage, just replace the bearing can be. The second is that the contact roller is worn, and the original dynamic balance is destroyed, causing abnormal vibration. In this case, the sand roller must be removed for maintenance.

6.Intermittent rotation or non-rotation of the lower conveyor roller when the sander is empty 

The above cannot normally be observed when working. This situation can only be detected when the vehicle is empty. The cause is partial or total wear of the worm gears in the worm gear reduction that transmits the power.

Solution: Although it will not affect the work, the other worm gears will have a shorter life and cause more damage due to the increased work load. Therefore, once this situation is found, it should be replaced immediately.

7.The size of the sanding plate has changed since the belt was replaced

The cantilever of the sander fluctuates greatly in position when the locking block is loosened or locked. Normal should be within 0.5mm. If it is too large, when the locking block locks the cantilever, the difference in the size of the locking force will cause a difference in the repeat accuracy of the cantilever, causing fluctuations in the size of the sanding plate and directly affecting the sanding accuracy of the sander.

 Solution: When the cantilever error is too large (more than 0.5mm), the locking block fixing bolt should be unscrewed and adjusted appropriately. At the same time when replacing the sanding belt, the locking block locking strength should be consistent

8.Slipping of the main drive belt

Both the Q and M sanders use high speed flat belts. This form of transmission is theoretically more efficient than v-belt transmission. However, in actual use, it will produce belt runout or slipping phenomenon, which is mainly caused by improper adjustment.

  Solution: The belt should be adjusted in strict accordance with the requirements of the belt extension rate of 1.5-2%, and the belt on both sides of the same elasticity. When the adjustment is completed according to the requirements, the sander is tested for operation. Especially when the main motor current suddenly rises, observe whether the belt runs off. If it runs off, the second adjustment should be made.

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